In recent years, importance has been placed on improving the quality of an operator's telephone calls at call centers. The evaluation of the call quality of an operator is made by, for example, a supervisor controlling the operators. As one viewpoint of evaluating the call quality, for example, there is the superposition (overlapping) of the speech of the operator and the speech of the customer. There is conventionally known a technology of giving a low evaluation for the call quality of the operator when the speeches of the operator and the customer are superposed (see patent document 1).    Patent document 1: Japanese Laid-Open Patent Publication No. 2007-288242
However, in an actual telephone call from the customer, even when the speeches of the operator and the customer are superposed, there are cases where it is not determined as the operator's fault. For example, when the customer is unable to give smooth explanations and is speaking in an awkward manner, the operator may say something like “that is to say, you mean so and so”, overlapping the customer's speech, to summarize the customer's question in place of the customer, to confirm the intention of the customer's question. In this case, the call quality of the operator is not to be given a low evaluation. However, in the conventional technology, it is not possible to objectively determine whether this is the case.
As described above, in a technology of giving a low evaluation for the call quality of the operator when the speeches of the operator and the customer are superposed, the call quality of the operator may be evaluated erroneously. Therefore, the supervisor is unable to accurately evaluate the call quality of the operator, and as a result, the supervisor is unable to appropriately supervise the operator.